Skip to contents
bslib 0.5.0.9000
  • Get Started
    Shiny dashboards Any Bootstrap project Theming
  • Theming
    Theming variables Utility Classes Custom components
  • Components
    Cards Sidebars Value Boxes
  • Layouts
    Multiple columns Multiple panels Filling layout
  • Reference
  • News

Cards

Source: vignettes/cards.Rmd
cards.Rmd

Cards are a common organizing unit for modern user interfaces (UI). At their core, they’re just rectangular containers with borders and padding. However, when utilized properly to group related information, they help users better digest, engage, and navigate through content. This is why most successful dashboard/UI frameworks make cards a core feature of their component library. This article provides an overview of the API that bslib provides to create Bootstrap cards.

Setup code

To demonstrate that bslib cards work outside of Shiny (i.e., in R Markdown, static HTML, etc), we’ll make repeated use of statically rendered htmlwidgets like plotly and leaflet. Here’s some code to create those widgets:

library(bslib)
library(shiny)
library(htmltools)
library(plotly)
library(leaflet)

plotly_widget <- plot_ly(x = diamonds$cut) %>%
  config(displayModeBar = FALSE) %>%
  layout(margin = list(t = 0, b = 0, l = 0, r = 0))

leaflet_widget <- leafletOptions(attributionControl = FALSE) %>%
  leaflet(options = .) %>%
  addTiles()

Shiny usage

Cards work equally well in Shiny. In the examples below, replace plotly_widget with plotlyOutput() and leaflet_widget with leafletOutput() to adapt them for Shiny server-rendered plots/maps.

Hello card()

A card() is designed to handle any number of “known” card items (e.g., card_header(), card_body(), etc) as unnamed arguments (i.e., children). As we’ll see shortly, card() also has some useful named arguments (e.g., full_screen, height, etc).

At their core, card() and card items are just an HTML div() with a special Bootstrap class, so you can use Bootstrap’s utility classes to customize things like colors, text, borders, etc.

card(
  card_header(
    class = "bg-dark",
    "A header"
  ),
  card_body(
    markdown("Some text with a [link](https://github.com)")
  )
)
A header

Some text with a link

Implicit card_body()

If you find yourself using card_body() without changing any of its defaults, consider dropping it altogether since any direct children of card() that aren’t “known” card() items, are wrapped together into an implicit card_body() call.1 For example, the code to the right generates HTML that is identical to the previous example:

card(
  card_header(
    class = "bg-dark",
    "A header"
  ),
  markdown("Some text with a [link](https://github.com).")
)
A header

Some text with a link.

Restricting growth

By default, a card()’s size grows to accommodate the size of it’s contents. Thus, if a card_body() contains a large amount of text, tables, etc., you may want to specify a height or max_height. That said, when laying out multiple cards, it’s likely best not to specify height on the card(), and instead, let the layout determine the height layout_column_wrap().

Although scrolling is convenient for reducing the amount of space required to park lots of content, it can also be a nuisance to the user. To help reduce the need for scrolling, consider pairing scrolling with full_screen = TRUE (which adds an icon to expand the card’s size to the browser window). Notice how, when the card is expanded to full-screen, max_height/height won’t effect the full-screen size of the card.

card(
  max_height = 250,
  full_screen = TRUE,
  card_header(
    "A long, scrolling, description"
  ),
  lorem::ipsum(paragraphs = 3, sentences = 5)
)
A long, scrolling, description

Dolor ante proin ornare habitasse feugiat posuere nullam dapibus et parturient! Justo malesuada taciti tellus consequat blandit ante natoque nam. Vulputate platea molestie risus vehicula posuere nullam vel nunc? Vehicula conubia molestie fermentum etiam vivamus quam himenaeos netus volutpat accumsan. Accumsan eu nulla metus parturient augue ultricies – erat malesuada, hac, senectus dictumst dictumst libero aliquet dapibus cum nibh pretium.

Adipiscing ullamcorper litora nisl hac etiam sollicitudin ornare ultrices. Arcu blandit erat curae, lacinia sociosqu viverra sem. Venenatis morbi himenaeos convallis dis potenti dapibus ut nibh litora duis. Massa bibendum molestie curabitur vehicula; risus varius at laoreet? Viverra mattis ultricies integer, libero fusce integer consequat egestas velit erat maecenas volutpat est nisi potenti.

Amet rutrum mauris suspendisse eleifend dictumst scelerisque risus taciti. Litora eleifend venenatis proin – non eleifend – imperdiet leo iaculis maecenas condimentum potenti. Vitae bibendum aliquam fringilla erat velit feugiat suspendisse! Dictum suspendisse volutpat ultricies condimentum. Velit nisl sollicitudin porta tristique; dignissim tempor tempor pretium laoreet luctus malesuada, duis suspendisse curae ultricies elementum tempus.

Expand

Filling outputs

A card()’s default behavior is optimized for facilitating filling layouts. More specifically, if a fill item (e.g., plotly_widget), appears as a direct child of a card_body(), it resizes to fit the card()s specified height. This means, by specifying height = 250 we’ve effectively shrunk the plot’s height from its default of 400 down to about 200 pixels. And, when expanded to full_screen, the plot grows to match the card()’s new size.

card(
  height = 250,
  full_screen = TRUE,
  card_header("A filling plot"),
  card_body(plotly_widget)
)
A filling plot
Expand

Most htmlwidgets (e.g., plotly, leaflet, etc) and some other Shiny output bindings (e.g, plotOutput(), imageOutput(), etc) are fill items by default, so this behavior “just works” in those scenarios. And, in some of these situations, it’s helpful to remove card_body()’s padding, which can be done via spacing & alignment utility classes.

card(
  height = 275,
  full_screen = TRUE,
  card_header("A filling map"),
  card_body(
    class = "p-0",
    leaflet_widget
  ),
  card_footer(
    class = "fs-6",
    "Copyright 2023 RStudio, PBC"
  )
)
A filling map
Copyright 2023 RStudio, PBC
Expand

Fill item(s) aren’t limited in how much they grow and shrink, which can be problematic when a card becomes very small. To work around this, consider adding a min_height on the card_body() container. For example, try using the handle on the lower-right portion of this card example to make the card taller/smaller.

This interactive example is a bit contrived in that we’re using CSS resize to demonstrate how to make plots that don’t shrink beyond a certain point, but this concept becomes quite useful when implementing page-level filling layouts (i.e., page_fillable()) with multiple cards.

card(
  height = 300,
  style = "resize:vertical;",
  card_header("Plots that grow but don't shrink"),
  card_body(
    min_height = 250,
    plotly_widget,
    plotly_widget
  )
)
Plots that grow but don't shrink

Troubleshooting fill

As you’ll learn more about in filling layouts, a fill item loses its ability to fill when wrapped in additional UI element that isn’t a fillable container. To fix the situation, use as_fill_carrier() to allow the additional element to carry the potential to fill from the card_body() down to the fill item.

Multiple card_body()

A card() can have multiple card_body()s, which is especially useful for:

  1. Combining both resizable and non-resizable contents (i.e., fill items and non-fill).
  2. Allowing each card_body() to have their own styling (via inline styles and/or utility classes) and resizing limits (e.g., min_height).

For example, when pairing filling output with scrolling content, you may want min_height on the filling output since the scrolling content will force it to shrink:

card(
  height = 375,
  full_screen = TRUE,
  card_header(
    "Filling plot, scrolling description"
  ),
  card_body(
    min_height = 200,
    plotly_widget
  ),
  card_body(
    class = "lead container",
    lorem::ipsum(paragraphs = 10, sentences = 5)
  )
)
Filling plot, scrolling description

Lorem volutpat quam sapien inceptos et felis porttitor? Tempor hac placerat aliquam tincidunt neque varius senectus sed. Vulputate ad quam sociosqu sem tristique: mauris, nisi placerat penatibus – semper suscipit habitasse. Penatibus vitae quis ante egestas laoreet egestas posuere metus luctus urna cum habitant facilisis. Nec curae rhoncus etiam est: cubilia fringilla ante laoreet.

Consectetur orci fusce feugiat libero nec: scelerisque eget luctus faucibus. Felis tempor faucibus vulputate leo molestie aenean risus nulla dis facilisis. Maecenas netus eget dis fames turpis ligula urna suspendisse, dui malesuada nostra aliquam? Massa auctor fusce taciti hac suspendisse? Parturient nulla eget; feugiat enim fusce mus dapibus consequat, mauris torquent nam nulla dictumst.

Adipiscing senectus egestas maecenas hendrerit, nunc, sed nibh viverra, congue elementum, conubia conubia ridiculus. Torquent in, dictumst condimentum lectus auctor tellus aenean imperdiet class etiam quisque! Class malesuada vehicula dis, nunc gravida, libero nisl. Habitant curabitur fermentum ut eleifend accumsan vel dapibus! Suspendisse venenatis vivamus facilisis netus molestie est mattis.

Adipiscing netus nibh imperdiet elementum volutpat, porta dui purus? Semper metus aliquam, hac felis, posuere viverra enim, tellus enim dignissim curabitur potenti. Nisi pretium vehicula consequat lectus hendrerit sodales duis nunc dictumst? Proin est condimentum platea dictum mi sed est ante. Torquent cubilia sollicitudin consequat pretium diam quisque?

Lorem dapibus vivamus sed, dis himenaeos commodo senectus duis. Ultricies imperdiet – faucibus cubilia habitasse, quis, litora dis erat lobortis! Hendrerit per curabitur cum felis platea magna id. Justo sociis fusce orci nostra dignissim, conubia nullam. In sociosqu sed dis bibendum tempor congue vehicula, mauris urna inceptos rutrum iaculis etiam.

Ipsum congue felis feugiat euismod ultrices erat molestie porttitor fusce. Consequat praesent augue primis elementum leo consequat orci at vivamus senectus. Nibh rhoncus pellentesque dignissim, id nulla orci feugiat. Integer enim etiam, lobortis, nisi eu at conubia cras, ac nunc? Aliquet nullam pellentesque volutpat blandit eleifend, suscipit faucibus faucibus nulla; gravida, mus praesent egestas nisi aliquam convallis nunc venenatis litora.

Sit suscipit augue dictum faucibus viverra, pretium turpis suspendisse dictumst accumsan congue! Senectus nibh velit sapien nunc sapien mattis. Nisi blandit netus magna aliquam, ullamcorper nunc. Ultrices sapien cursus netus lobortis porta nunc erat. Himenaeos tempor platea maecenas, vestibulum bibendum risus odio porta fames tincidunt duis magnis pulvinar non metus velit montes massa cum a auctor!

Sit himenaeos pretium nibh, felis proin dictumst netus nec accumsan sociosqu quisque cubilia ultricies turpis? Congue augue malesuada venenatis, dictum mollis fringilla. Dictumst placerat est tristique duis purus cras, scelerisque aptent potenti. Litora habitant venenatis laoreet, ultricies sagittis senectus, massa porttitor aliquet. Ullamcorper netus eros accumsan suscipit est viverra, class sollicitudin ultrices cursus suspendisse.

Dolor libero blandit malesuada massa morbi, ultrices etiam sapien? Sed etiam orci tempus duis turpis per, ridiculus a fames semper. Nec nisi turpis sociis iaculis; varius potenti nascetur? Fringilla velit rhoncus sagittis mollis dictumst neque dictumst habitant, varius elementum aptent tincidunt cras platea? Nostra ac leo ultrices pharetra, vivamus sociis pellentesque mollis phasellus erat sapien aptent erat euismod curae ut scelerisque lectus.

Lorem hendrerit hendrerit et, iaculis neque auctor sem. Ullamcorper at suscipit massa enim vulputate justo, venenatis interdum enim? Quisque praesent non viverra sollicitudin cum – lacus natoque rhoncus rutrum fringilla netus. Velit nec, nullam euismod, auctor tellus per montes molestie – ac tortor. Congue himenaeos diam libero nec mi ridiculus felis – nibh placerat suspendisse hac cubilia.

Expand

Also, when the content has a fixed size, and should not be allowed to scroll, set fill = FALSE:

card(
  height = 350,
  full_screen = TRUE,
  card_header(
    "Filling plot, short description"
  ),
  plotly_widget,
  card_body(
    fill = FALSE,
    card_title("A subtitle"),
    p(class = "text-muted", "And a caption")
  )
)
Filling plot, short description
A subtitle

And a caption

Expand

Multiple columns

As you’ll learn in column-based layouts, layout_column_wrap() is great for multi-column layouts that are responsive and accommodate for filling output. Here we have an equal-width 2-column layout using width = 1/2, but it’s also possible to have varying column widths.

card(
  height = 350,
  full_screen = TRUE,
  card_header("A multi-column filling layout"),
  card_body(
    min_height = 200,
    layout_column_wrap(
      width = 1/2,
      plotOutput("p1"),
      plotOutput("p2")
    )
  ),
  lorem::ipsum(paragraphs = 3, sentences = 5)
)
A multi-column filling layout

Amet felis placerat ante ultricies mi elementum. Etiam lacus lectus neque etiam mauris suspendisse massa nostra faucibus imperdiet! Turpis est taciti; a dis vel lacus vel neque tempor porttitor? Vivamus mauris lacinia mauris augue faucibus mollis ante cras. Parturient et habitant ad vivamus facilisis, himenaeos cubilia fermentum luctus cum fames accumsan nam aenean curabitur conubia.

Lorem elementum dictum fermentum nisl velit. Auctor habitasse, habitasse fames augue, sodales fringilla urna! Dapibus senectus dapibus fringilla, a egestas ultricies nulla sapien rhoncus! Velit augue nisi volutpat tincidunt posuere ullamcorper massa commodo maecenas: fringilla varius vehicula. Varius erat tristique sodales quisque eu purus libero dui taciti lacinia, semper tempor mus faucibus?

Dolor nullam nec vehicula congue ultricies? Ligula at senectus bibendum: duis curabitur, litora maecenas curae massa eget vehicula! Praesent convallis tortor suspendisse egestas suscipit leo sagittis volutpat ridiculus, condimentum fringilla lacus. Sodales habitant velit erat fusce tristique orci, luctus ullamcorper orci himenaeos eu posuere. Non a dui, malesuada etiam natoque magnis senectus!

Expand

Multiple cards

layout_column_wrap() is especially nice for laying out multiple cards since each card in a particular row will have the same height (by default). Learn more in column-based layouts.

layout_column_wrap(
  width = 1/2,
  height = 300,
  card(full_screen = TRUE, card_header("A filling plot"), plotly_widget),
  card(full_screen = TRUE, card_header("A filling map"), card_body(class = "p-0", leaflet_widget))
)
A filling plot
Expand
A filling map
Expand

Multiple tabs

navset_card_tab() and navset_card_pill() make it possible to create cards with multiple tabs or pills. These functions have the same full_screen capabilities as normal card()s as well some other options like title (since there is no natural place for a card_header() to be used). Note that, each nav_panel() object is similar to a card(). That is, if the direct children aren’t already card items (e.g., card_title()), they get implicitly wrapped in a card_body().

library(leaflet)
navset_card_tab(
  height = 450,
  full_screen = TRUE,
  title = "HTML Widgets",
  nav_panel(
    "Plotly",
    card_title("A plotly plot"),
    plotly_widget
  ),
  nav_panel(
    "Leaflet",
    card_title("A leaflet plot"),
    leaflet_widget
  ),
  nav_panel(
    shiny::icon("circle-info"),
    markdown("Learn more about [htmlwidgets](http://www.htmlwidgets.org/)")
  )
)
HTML Widgets
  • Plotly
  • Leaflet
A plotly plot
A leaflet plot

Learn more about htmlwidgets

Expand

Sidebars

As you’ll learn more about in sidebar layouts, layout_sidebar() just works when placed inside in a card(). In this case, if you want fill items (e.g., plotly_widget) to still fill the card like we’ve seen before, you’ll need to set fillable = TRUE in layout_sidebar().

card(
  height = 300,
  full_screen = TRUE,
  card_header("A sidebar layout inside a card"),
  layout_sidebar(
    fillable = TRUE,
    sidebar = sidebar(
      actionButton("btn", "A button")
    ),
    plotly_widget
  )
)
A sidebar layout inside a card
Expand

Static images

card_image() makes it easy to embed static (i.e., pre-generated) images into a card. Provide a URL to href to make it clickable. In the case of multiple card_image()s, consider laying them out in multiple cards with layout_column_wrap() to produce a grid of clickable thumbnails.

card(
  height = 300,
  full_screen = TRUE,
  card_image(
    file = "shiny-hex.svg",
    href = "https://github.com/rstudio/shiny"
  ),
  card_body(
    fill = FALSE,
    card_title("Shiny for R"),
    p(
      class = "fw-light text-muted",
      "Brought to you by RStudio."
    )
  )
)
Shiny for R

Brought to you by RStudio.

Expand

Flexbox

Both card() and card_body() default to fillable = TRUE (that is, they are CSS flexbox containers), which works wonders for facilitating filling outputs, but it also leads to surprising behavior with inline tags (e.g., actionButton(), span(), strings, etc). Specifically, each inline tag is placed on a new line, but in a “normal” layout flow (fillable = FALSE), inline tags render inline.

card(
  card_body(
    fillable = TRUE,
    "Here's some", tags$i("inline"), "text",
    actionButton("btn1", "A button")
  ),
  card_body(
    fillable = FALSE,
    "Here's some", tags$i("inline"), "text",
    actionButton("btn2", "A button")
  )
)
Here's some inline text
Here's some inline text

That said, sometimes working in a flexbox layout is quite useful, even when working with inline tags. Here we leverage flexbox’s gap property to control the spacing between a plot, a (full-width) button, and paragraph. Note that, by using markdown() for the paragraph, it wraps the results in a <p> tag, which means the contents of the paragraph are not longer subject to flexbox layout. If we wanted, we could do something similar to render the actionButton() inline by wrapping it in a div().

card(
  height = 325, full_screen = TRUE,
  card_header("A plot with an action links"),
  card_body(
    class = "gap-2 container",
    plotly_widget,
    actionButton(
      "go_btn", "Action button",
      class = "btn-primary rounded-0"
    ),
    markdown("Here's a _simple_ [hyperlink](https://www.google.com/).")
  )
)
A plot with an action links

Here's a simple hyperlink.

Expand

In addition to gap, flexbox has really nice ways of handling otherwise difficult spacing and alignment issues. And, thanks to Bootstrap’s flex utility classes, we can easily opt-in and customize defaults.

card(
  height = 300, full_screen = TRUE,
  card_header(
    class = "d-flex justify-content-between",
    "Centered plot",
    checkboxInput("check", " Check me", TRUE)
  ),
  card_body(
    class = "align-items-center",
    plotOutput("id", width = "75%")
  )
)
Centered plot
Expand

Shiny

Since this article is statically rendered, the examples here use statically rendered content/widgets, but the same card() functionality works for dynamically rendered content via Shiny (e.g., plotOutput(), plotlyOutput(), etc).

An additional benefit that comes with using shiny is the ability to use getCurrentOutputInfo() to render new/different content when the output container becomes large enough, which is particularly useful with card(full_screen = T, ...). For example, you may want additional captions/labels when a plot is large, additional controls on a table, etc (see the value boxes article for a clever use of this).

# UI logic
ui <- page_fluid(
  card(
    max_height = 200,
    full_screen = TRUE,
    card_header("A dynamically rendered plot"),
    plotOutput("plot_id")
  )
)

# Server logic
server <- function(input, output, session) {
  output$plot_id <- renderPlot({
    info <- getCurrentOutputInfo()
    if (info$height() > 600) {
      # code for "large" plot
    } else {
      # code for "small" plot
    }
  })
}

shinyApp(ui, server)

Appendix

The following CSS is used to give plotOutput() a background color; it’s necessary here because this documentation page is not actually hooked up to a Shiny app, so we can’t show a real plot.

.shiny-plot-output {
  background-color: #216B7288;
  height: 400px;
  width: 100%;
}

On this page

Developed by Carson Sievert, Joe Cheng, Garrick Aden-Buie, Posit Software, PBC.

Site built with pkgdown 2.0.7.